Centrifugal countercurrent contact devices



' w. J. PODBIELNIAK 2,880,929

CENTRIFUGAL COUNTERCURRENT CONTACT DEVICES 5 Sheets-Sheet 1 April 7 1959 Filed June '7, 195] Inga/22507, w CLZW Q ygomwm, j/madagfl mr M April 7, 1959 w. J. PODBIELNIAK CENTRIFUGAL COUNTERCURRENT CONTACTDEVICES Filed Jun 7, 1951 5 Sheets-Sheet 2 wade? April 1959 'w. J.. PODBIELNIAK I 2,880,929

CENTRIFUCAL COUNTERCURRENT CONTACT DEVICES Filed June 7, 195] 5 Sheets-Sheet 4 'N k d1 1 N N N W XQUQMM Q zawamr W. J. PODBIELNIAK CENTRIFUGAL COUNTERCURRENT CONTACT DEVICES A ril 7, 1959 5 Sheets-Sheet 5 Filed June '7, 1951 Ida/Z0 United StatesPatent O CENTRIFUGAL COUNTERCURRENT CONTACT I I DEVICES Walter Joseph Podbielniak, Chicago, 111., assignor of onehalf to Wladzia G. Podbielniak Application June 7, 1951, Serial No. 230,313

7 Claims. (Cl. 233--15) The present invention relates to improvements in centrifugal countercurrent contacting devices and more particularly to devices of this character which are intended for effecting countercurrent contact between liquids of different densities which are I immiscible or partly so. Such countercurrent contact may be efiected, for example, for purposes of solvent extraction, chemical treatment and the like and may also be employed for countercurrent contact between liquids and gases or vapors, if so desired.

The device of the present invention is more particularly intended for use in small scale operation; for example, in the manufacture of some types of pharmaceuticals and other fine chemicals in which relatively small amounts of material are to be handled, and in pilot plant operations, in which the primary objective, is to conduct experimental work to determine efficiency of operation and to develop conditions for use in larger scale operation. The apparatus of the invention is so constructed that the conditions secured in its operation may be readily varied in accordance with the desires and convenience of the operator.

The invention will be fully understood from the following description, illustrated by the accompanying drawings, in which:

Fig. 1 is a side elevation, partly in section, of apparatus embodying the present invention;

Fig. 2 is a longitudinal elevation, partly in section, of the apparatus of Fig. 1;

Fig. 3 is a broken fragmentary view, partly in section, transversely through a rotor arm of the device of Figs. 1 and 2;

Fig. 4 is a detail view in side elevation, partly in section, of the rotor arm shown in Fig. 3 with parts of the rotor shaft;

Fig. 5 is a detail perspective view of the plug used as a closure for the radial chamber in the rotor of Figs. 3 and 4;

Fig. 6 is a detail view of a perforate disk used as a partition member within the operating space in the rotor arm as illustrated in Figs. 2 and 3;

Fig. 7 is a spacer ring as employed between the disks in the working space in the rotor arm of Figs. 3 and 4;

Fig. 8 is a detailed sectional view through one end of the rotor shaft and part of the rotor arm as shown in Figs. 2, 3 and 4;

Fig. 9 is a broken sectional view through a modified form of rotor arm; and

Fig. 10 is a broken sectional view through another modified form of rotor arm.

The embodiment of the apparatus illustrated has a suppotting framework 10, within which is mounted a rotor 11 of generally cylindrical form, upon which are mounted the rotor arms 12 and 13, shown in dotted lines in Fig. l. A stationary housing 14, within which the rotor operates, is mounted as will be more fully hereinafter described.

Referring more particularly to Figsr2 and 8, the rotor "Ice 11 is provided with shaft extensions 15 and 16. Since the mounting and construction of these shaft extensions are similar, except as hereinafter indicated, only the one at the right of the rotor as it appears in Fig. 2 is shown in detail in Fig. 8 and it will be understood that, except as hereinafter pointed out, the internal construction within the shaft extension 16 is similar to that shown in connection with shaft extension 15.

The shaft extension 15 is rotatably mounted in the stationary journal sleeve 17 through the intermediary of a ball bearing 17a, the journal sleeve 17 being carried in the support 10. Shaft extension 16 is similarly mounted. Provision is made through these shaft exten sions, as hereinafter more fully described, for the supply of the light and heavy liquids to the apparatus prior to the centrifugal contacting operation and for the removal of the light and heavy liquids after the centrifugal contacting operation has been completed.

The rotor arm 12 is provided with a restricted bore or working chamber 18 which extends outwardly from a point near the axis of rotation of the rotor to the end of the arm. In the form illustrated in Figs. 1 to 8, this chamber extends radially, but, if desired, it may be inclined to the radius of the rotor. At the base or inner end of this bore, a short plug 19, having a central opening 20 drilled through it, is secured, the opening 20 communicating with an opening 21 which is drilled to meet another opening 22 extending to the axis of the shaft for the supply of heavier liquid to the interior chamber 18 in the arm 12. The plug 19 projecting into the radial bore or chamber 18 leaves an annular space surrounding it and from this another bore or opening 23 is provided for the egress of the lighter liquid discharging from the chamber 18 after the countercurrent contact operation has been completed.

The bore or chamber 18 is enlarged a short distance from the axis to form a shoulder 24 and upon this shoulder there are mounted an alternate sequence of perforated disks 25 and spacer rings 26 forming a series of compartments extending outwardly from the axis of the rotor. As indicated in the drawings the spacer rings may be of gradually decreasing size so that the radial distances between the successive disks decrease as the radial distance increases, as will be more fully pointed out here inafter. However, in some cases it is desirable that the disks be equidistant or even that the'spacings between them increase as the radius increases. The series of disks and spacers are held in place by a screw plug 27, which also closes chamber 18. The inner portion of screw plug 27 is provided with a central cavity surrounded by spaced lugs 28, as illustrated in Fig. 5, the spacings between the lugs providing passages for the ingress and egress of liquids. These passages communicate through ports or openings 29 and 30, suitably on opposite sides of the arm 12 near its outer extremity, with conduits 31 and 32, respectively, which are suitably drilled through the arm 12. The openings formed by the drilling of ports 29 and 30 are suitably closed by plugs 33, and those formed by drilling conduits 31 and 32 by plugs 34. I

Suitable provision is made for supplying and removing the liquids involved in the operation. Thus an axial bore or opening 35, of varying diameter, is drilled through the rotor shaft member 15 and terminates within the rotor in a reduced portion 36, forming a small chamber. This chamber communicates through opening 38 drilled radially of the rotor and a short external conduit section 39 with a port 40 drilled through the wall of rotor arm 12 to communicate with the conduit 32 at its inner end. Light liquid, which enters the chamber 36 as hereinafter described, may thus be conducted into the rotor arm and enters the working chamber 18 at the outer end thereof,

thmughport 30, to be forced-under pressure through the htter'against'the centrifugal force operating within the rotor.

Within the axial bore or opening 35 in theshaft member '15, there is inserted a tube 41, surrounded by a sleeve 42, which is spaced from the tube 41 to provide between them the annual passageway 43. The sleeve 42 is made up of three parts, welded together to form an integral structure, these being an innermost stub or end portion 420, -anintcrmcdiate cylindrical portion 42b and an outer end portion 42c. The sleeve 42 as a whole is rigidly secured within the axial opening 35, suitably by a shrink fit, and the tube 41 is likewise rigidly secured in position in a similar way within the sleeve, the end portions of the latter having their internal diameters reduced as It and 45 for this purpose. The stub or end portion 420 has openings 46 drilled through it, communicating with the annular passageway 43 between the tube 41 and the sleeve 42 at one end, and at the other end opening into an annular cavity 47 formed by a groove cut into the body of the stub orcnd portion 42a of the sleeve 42. The means for providing ingress and egress to the interior of the tube 41 and the annular passageway 43 will be described hereinafter.

Heavy liquid is withdrawn from the outer end of the motor arm andintroduced into the conduit 43 in the shaft 15 where discharged from the system in the following manner:

The heavy liquid separated in the operation of the centrifugal contactor collects at the outer end of the rotor arm andpasses through the opening 29 and the conduit 31, through which it travels toward the axis of the rotor. It passes out of the conduit 31 through the opening 48 drilled in the wall of the rotor arm, then through the outer'conduit member 49 and through the hole 50 which bdrillcd axially through the rotor 15 and opens into the annularspace 47 in the stub or end portion 42a of the time 42. The heavy liquid is then conducted through openings 46 into the annular passageway 43 surrounding the tube 42.

The annular passageway 43, as heretofore indicated, is continued to the outer end of the sleeve portion 42c, where: the internal diameter of this portion of the sleeve is reduced by the formation of a shoulder 51, which termimics the annular conduit 43, the tube being closely fitted into the sleeve beyond this point. An angular opening 52 is drilled through the end portion of the Sleeve 42 at about the pointwhere the latter terminates and this opening 52 dischargesinto an annular chamber 53 .in the stationary cap 54. From the latter, an external conduit 55 carries the heavy liquid out of the device.

vFor the passage of the liquid from the exterior of the device into the interior of the tube 41, suitable conduit and seal means are provided, since this liquid must pass through the stationary .cap 54. As indicated above, at its outer end the tube 41' is closely fitted to the end of the sleeve 42. The rotating metallic seal ring 56, L-shaped in cross section and provided with a center opening 57 corresponding in position to the opening of the tube 41, is held in contact with a gasket 57a at the end of the sleeve 42by a second carbon seal ring 58, these rings rotatingwith the, sleeve 42 and the shaft member 15. A nonrotating, slidablc slceveelike retainer .59, provided at its inner end with a flange .60 is forced against the seal member 58 by the spring plungers 61, of which a suitable number are provided at intervals around the shaft. An annular flanged seal ring 62, suitably of Teflon," is mounted against a shoulder formed on the retainer 59 andis held in place ,byaynut .63. .A suitable gasket of Teflon or other inert materialmay be provided between thelretainer .59 and the rotating seal member .58. A sealed passageway iS'Ifl'lUS provided for the discharge of liquids from theinterior of the tube 41 through the cen' trill opening 57 insealmemberSfi, and corresponding openings in the :seal member :58 andrctainer and 4 f these openings communicate with a chamber 64 formed in the end of the cap 54, which is provided with a ta'pped opening 65, into which an external pipe or conduit 66 (Fig. 2) may be screwed.

As set forth hereinbefore, the shaft member 15 is mounted in a ball bearing 17a within a stationary journal sleeve 17. At the inner side of the ball bearing, to aid in retaining it in position, there is secured to the shaft member 15 a flanged ring 70, which interlocks with the journal sleeve 17 but does not contact the latter. Ring 70 is free to rotate with the shaft. At the opposite side of the inner race of the ball bearing 17, a threaded locking ring 71 is screwed on the shaft member 15 and holds the ball bearing 17a in position. The shaft member 15 is made sufficiently long to permit the attachment to it of the drive pulley 72, which is secured to the shaft member in any suitable manner, as by the key 73 and the ring nut 74. Beyond the ring nut 74,-the shaft member 15 is provided with a shoulder 75 against which there is seated a metallic seal ring 76. This is engaged by the carbon seal ring 77, which is held in position by the spring pressed retainer 78, suitable gaskets being pro vided between the retainer 78 and the seal ring 77, and between the seal ring 76 and the shoulder 75. A cup ring 79 of 'Tefion or other suitable inert material engages a shoulder near the end of the retainer 78 and is held in position by the ring nut 80. It will be apparent that the annular chamber 53 is thus sealed against leakage of fluid in both directions.

A stationary partial housing 81, which protects the drive pulley, is secured to the journal member 17 by means of a ring 82 which is held in position by bolts 83 at suitable intervals around the ring; and the cap54 is held in position against the housing 81 by a similar ring 84. Suitable means are provided for the supply and flow of lubricants for the shaft extension 15 and its associated parts.

As described, the shaft extension 15 and the associate-d parts provide conduit means for the continuous supply of light liquid to and the removal of heavy liquid from the outer end of the rotor arm. The shaft extension 16 is sirnilarly provided with conduit means for the supply of heavy liquid to and the discharge of light liquid from the inner end of the rotor arm. The shaft extension 16 is not as long as the shaft extension 15, since the drive pulley is not carried thereby, but otherwise the internal construction is similar. The inner end ofthis shaft extension is shown in section in Fig. 8 at the left. The internal tube or conduit corresponds to the internal tube 41 of shaft member 15 and the annular conduit 91 corresponds to the annular conduit 43 of shaft member 15. The tube 90 terminates in the chamber 92 at the end of the opening drilled in the shaft extension 16 and this chamber 92 communicates through openings 22 and 21 with the opening 20 in plug 19 in the base or axial end of the working chamber 18 in rotor 'arm 12. At its outer end,, heavy liquid entering the system is supplied through the conduit or pipe 93, which enters the opening corresponding to the pipe 66 at the end of the housing or cap 54, previously described. Heavy liquid may thus be supplied to the rotor through the pipe 93 and the internal tube 90 within the shaft 16.

Light liquid leaving the rotor arm passes out through the opening 23 at the axial end of rotor arm 12 and through a communicating opening 94 drilled inthe rotor shaft, which opening communicates with the annular chamber 95 corresponding to the annular chamber 47in the shaft member 15. From annular chamber 95, the light liquid passes through openings 96 ,into the annular conduit '91, and from the latter it discharges through the pipe 97 (Fig. 2) which corresponds to the pipe 55 in the assembly for shaft extension 15. Thus, provision is made rfor the supply of heavy liquid to and the withdrawal of light liquid from the inner end of-the rotor arm 12 continuously during operation.

The housing 14, which encases the rotor, is formed of a lower stationary portion 98, set in a frame 99 bolted to the support 10, and an upper portion 100 pivoted to the frame 99 and provided with suitable lockingv means 101, as a pivoted bolt. Both the lower and upper portions 98 and 100 of casing 14 are provided with cut out portions fitting, when the casing is closed, in groove 102 formed in journal sleeve 17.

While, for convenience in manufacture, the operating chamber is shown as of circular cross-section, it may be rectangular, elliptical or of other desired sectional form. In operation, either the heavy liquid or the light liquid introduced into the rotor chamber 18 may contain a dissolved constituent to be removed from it, the other liquid acting as a solvent for the dissolved constituent. Thus the heavy liquid may be, for example, an acid penicillin broth containing penicillin, and the light liquid may be amyl acetate or other suitable immiscible solvent for the penicillin. Or, on the other hand, the light liquid may be a kerosene cut containing n-butylamine, as more specifically referred to hereinafter, and the heavy liquid may be water.

Of the liquids entering the rotor chamber, the light liquid is forced into the device through a suitable pipe or conduit 66 secured to the tapped opening 65 in cap 54 as hereinbefore described. The light liquid passes through the center openings of retainer 59, seal member 58 and tube 41 into chamber 36 in shaft member 15. From chamber 36 it passes through opening 38 of the rotor, pipe 39 and port 40 into conduit 32, by which it is carried to port 30, where it enters the rotor chamber under sufiicient pressure to force it inwardly there through and to be discharged therefrom, as hereinafter described.

The heavy liquid enters the device in a similar manner through pipe 93 and through passages in shaft extension 16 corresponding to those above described for introduction of the light liquid through shaft extension 15. The heavy liquid passes through the internal passage of tube 90 into chamber 92, from which it passes through opening 22 in the shaft, opening 21 in the base of the rotor arm 12 and opening 20 in plug 19 into the interior of the rotor chamber 18 at a point in proximity to, but spaced from its innermost or axial part.

' Under the drive of the centrifugal force resulting from the rotation of the device, the heavy liquid is forced outwardly through the chamber 18 while the light liquid is forced inwardly under the pressure applied to it. Intimate intermingling of the liquids takes place in proximity to the openings in partitions 25 as the liquids pass through the chamber 18 in opposite directions, and possibly also in passage through the openings, while separation takes place in the compartments between the partitions. The extent and intimacy of intermingling of the liquids are controllable through control of the size and number of the openings; and the effectiveness and completeness of the intermediate separations of phases are controllable.

through control of the spacing of the partitions 25 and thereby of the volume of the compartments therebetween.

After completion of its travel through chamber 18 and its separation in the innermost compartment thereof, the light liquid is forced out through openings 23 and 94 into annular chamber 95 in shaft extension 16. The light liquid passes thence through openings 96 and annular conduit 91, and discharges through pipe 97 as hereinbefore described. The heavy liquid, after passage through chamber 18 and separation in the outermost compartment thereof, passes out through port 29, conduit 31, opening 48, outer conduit member 49 and opening 50 into annular passageway 47 in shaft extension 15. The heavy liquid then passes through annular passageway 43 and through opening 52 into chamber 53 .6 in cap 54, from which chamber the light liquid dis charges through external conduit 55 as hereinbefore dcscribed.

As has been pointed out' hereinbefore, the spacing between the perforated disks 25 in the radial operating chamber 18 may be equal or may, if desired, increase with increasing radius. It is-preferred, however, that the spacing between the disks decrease with increasing radius. Thus the spacing between the disks may be an inverse function of a power of the radius ranging from 0.5 to 2 and preferably from 0.7 to 1.5. Thus these spacings may vary inversely as the radius itself, as indicated approximately in the drawing. The openings in the disk may be circular perforations, or may be elliptical or rectangular slots and may vary in number from 1 to 3 or 4, or even more, depending upon the internal diameter of the working space within the spacer rings 26. The size and number of the openings or perforations may vary in accordance with the nature of the liquids being treated and the degree of efficiency or number of theoretical stages desired. Thus, when the liquids under treatment contain suspended mat ter or when very high eificiency is not desired, circular perforations of as much as 0.200 to 0.250 inch diameter may be employed. For very high efficiency, the size of the openings or perforations may be small in one dimen sion at least, thus apparently providing for a jet action of the fluids passing through the openings, since it appears probable that accentuated countercurrent exchange effect is secured through the intermixing resulting from the jetting of the liquids in their passage through these openings. Thus, for high efiiciency the openings may be restricted in at least one dimension and in this dimem sion they should not exceed 0.090 to 0.150 inch and in general should not be not less than about 0.007 to 0.010 inch. A minimum dimension of from 0.010 to 0.070 inch is preferred. If restricted in one dimension, it not necessary that they be restricted in the other, except as convenience dictates. Perforations may be circular, in which case their dimensions are the same in all directions, or they may be rectangular or oval in shape. Rectangular perforations or slots 0.040 to 0.090 inch wide and 0.100 to 0.150 long have been found to be suitable in high efiiciency operation. The length of the perforations or slots may be up to 0.5 inch or even longer, up to the width of the chamber, if desired. However, to avoid distortion it is preferred that they be not over 0.25 to 0.5 inch long. Where greater area of open ings is desired, it is preferable that a plurality of slots of shorter length be employed. The total area of the perforations may be varied in accordance with the cilia ciencies and capacities which are desired. It may be as much as 10% to 15% of the clear cross-sectional area of the operating chamber, or even higher. In general; for high efficiency, it is found that the total area of the perforations should be in the order of 1 to 5% of the clear cross-sectional area of the operating chamber. The total area of the perforations may vary with increasing radius; for example, it may 'be an inverse function of a power of the radius from 0.5 to 2, or may be the same, as illustrated in the drawing. The arm 13, which serves to counterbalance. the arm 12, is of a size and shape similar to the latter. It is likewise provided with a radial bore or chamber 102 corresponding to the working chamber 18 in arm 12. The bore 102 is internally threaded to receive a screw plug 103 and the position of the latter may be varied to dynamically balance the arm 12 and its associated parts during operation. Suitable driving means are provided for the rotor. Thus, as hereinbefore described, provision is made for the attachment on shaft extension 15 of the drive pulley 72, and the shaft and rotor may be driven from a motor or other suitable power source through belt 104.

1 An important use of the device illustrated is as an 7 Wntal .or: pilot plant device. [It lends itself readily 9, Variations ,inamounts of liquids .fed and also to variations in internal structure to determine their effects upon the capacity and efliciency of the apparatus. Thus, the perforated disks and clearance rings may be readily .l'emovedand replaced by other disks with different types, sizes .or total areasof perforations and with other spacin; zrings providingfor different spacing of the disks. When constructed of stainless steel or other noncorrosive metal, the device may be used for the handling of wide varieties of materials.v

As an example of the use of the device for small scale operation and to show the efliciency which can be secured with it, an operation will be described in which the heavy liquid used waswater and the light liquid a dosekerosene cut of 150 F. flash (closed cup). For test: purposes n-butylamine was dissolved in the kerosene cut in a concentration of 54.5 millimoles per liter. The internal diameter of the operating chamber, within the pacing rings, was ,4 inch. .26 disks were employed, the. innermost being at .a radius of 1.856 inch and spacingibetween the rings varying from 0.53 to 0.051 inch, substantially as an inverse function of R Each disk had a single perforation in the dorm of an approximately rectangular slt.0.060 x 0.150 inch. The ratio of keroaeneto water was 2.8:1, the rate of feed being 250 cc. n-butylamine containing kerosene per minute and 92 ee. water per minute. The temperature of the liquids entering was 26 C. The temperature of thelight liquid leaving the apparatuswas 29.9 C. and that of the heavy liquid leaving the apparatus was approximately 335 C; The water entering the systemwas free from butyl @mine. The rotor was rotated .at a rate of 5000 r.p.m.

Of the'liquids leaving the system, the concentration of thebutylamine in the light liquid was reduced to ap proximately 9 millimoles per liter and the concentration ofthe butylamine in the water leaving the apparatus was 130 millimoles per liter. On comparison with the known data on the equilibrium distribution of n-butylarnine between water and kerosene, the .efiiciency of operation was found to be the equivalent of 8 stages.

In the device as illustrated, opposed rotor arms are provided in one of which the spaced perforated disks or partition members for elfecting the desired countercurrent exchange-are mounted, the other rotor arm serving as a counterbalance. As is readily apparent, if desired, both arms may be provided with such spaced perforated disks and with the auxiliary parts for supply and withdrawal of the fluids involved, or, indeed, the rotor may be provided with any desired number of rotor arms so provided. Instead of using arms, the rotor may be formed as a disk or as complementary disks in which the radially extending operating chamber or chambers are formed. Such chambers are formed so as to restrict the liquids present against free flow circumferentially and likewise to prevent flow of liquidfrom one chamber to another.

It is likewise apparent that the outwardly extending operating chambers may be disposed at an angle to a radius or on a curve providing an increasing deviation from the radius of the rotor away from the direction of rotation, but in its plane. In such case the perforated partitions are preferably placed tangentially to concentric circles having their common center at the axis of rotation of the rotor. The formation of eddy currents in the chambers between the perforated disks may thereby be, somewhat reduced and the efiectiveness of these chambers for the separation of the liquids increased.

Although in the device as hereinbefore described, the rotor "is shown as formed with two balanced a ms, in one or which the working chamber of the contactor is formed,

or in any desired manner. The rotor will, of course, in any case be dynamically balanced.

In Figs. 9 and 10, modified forms of construction of the compartments which together form the working chamher in the rotor arm of the contactor device are shown. In these forms of construction, instead of using perfo rated disks and spacers to subdivide the working chamber of the rotor arm, as illustrated in Figs. 2, 3 and .8. the radially spaced partitions are formed so that the shapes of the individual compartments within the arm are modified to reduce the inactive area within said compartments. In developing the shape of the individual compartments, the transverse movement and the swirl of liquid resulting from the rotational movement of the arms is taken into consideration.

Referring to Fig. 9, the numeral designates a rotor arm such as that designated 12 in Fig. 3. In the base of the rotor arm there is provided a substantially cylindrical compartment 106, corresponding to the'lowermost compartment of the arm 12 as previously described. This chamber is provided with the projecting nozzle or hollow plug 107 for the introduction of heavy liquid and the opening 108 for the withdrawal of light liquid, corresponding respectively to the nozzle or plug 19 and the opening 23 of the arm 12 as shown in Fig. 8.

In .the arm 105, as shown in Fig. 9, the spaced partitions between the compartments, which partitions may be integrally formed with the arm, are shaped to provide a succession of compartments 109, of similar size and shape, with openings formed in the partitions extending between these compartments and providing communication between them. The size .of these openings is governed by the same considerations which govern the size of the openings in perforated disks 25 as hereinbefore described.

The shape of the compartments 109 is developed with particular consideration to the intended direction of rotation of the arm 105, which is indicated by the arrow in connection with Fig. 9. Each of the chambers 10! is invertical section in the general form of a flattened ellipse having its axis slightly inclined away from the axis of the rotor in the direction of rotation. In developing the elliptoidal section of each of these compartments, it is flattened at the portions indicated in Fig. 9 by the nuumerals 111 and 112 in connection with one of the compartments illustrated. The portion 111, which is nearer to the axis of the rotor, is flattened so that no portion of the chamber will lie inside of a line tangent to the circumference of a circle drawn through the point where the discharge opening 110 from the next inner compartment enters the particular compartments under consideration and, if desired, the flattened portion 111 may itself be in section a circular or elliptical arc tangent to such a line. Similarly, the portion of the section of the compartment indicated by the numeral 112 is so formed that no part thereof lies outside of a line'tangent to a circle drawn through the point where the opening 110 to the next outer compartment meets the wall of the compartment under consideration. The surface 112 may be in section a circular or elliptical arc tangent to such a line.

The outermost compartment 109 discharges into a terminal compartment 113, which has the generalform in vertical section of a sector of an ellipse with the surface 114 flattened in the same manner as described in connection with the surface 111 of the compartments 109. The section of the chamber 113 tapers to its outer end, at which heavy liquid discharges from the Fontpartment throughthe openings 115 and 116, being thereafter handled in the same manner as previously described in .connection with the discharge of heavy liquid from the rotor arm '12. Light liquid is supplied at an inner point within the compartment 113 through the conduits or ped- 8 11 n All of the compartments formed in arm 105 may suitably be circular in transverse section.

Fig. 10 illustrates a further modified form. In this figure the numeral 120 designates the rotor arm, the direction of rotation, as shown by the arrow, being opposite that of the arm shown in Fig. 9. In this form of arm, as in that of Fig. 9, a compartment of circular cross sectron 121 is formed in the base of the arm, and a nozzle or hollow plug 122 is provided for the supply of heavy liquid and an opening 123 for the discharge of light liquid from the arm in connection with the contacting operation.

'A series of successive compartments 124 are formed in the arm with openings 125 between them. The chambers 124 are in vertical section of flattened elliptical form, similar to the compartments 109 in the arm of Fig. 9; but in the arm of Fig. 10, the compartments are successively smaller in size, the gradient in size being based upon the same considerations which determine the spacing of successive disks in the rotor arm of Fig. 3, as hereinbefore set forth. The sizes and numbers of the openings 125 are likewise based upon the same considerations which determine the sizes and number of openings in the :fhslas1 1n the rotor arm 12 of Fig. 3, as hereinbefore set In the arm of Fig. 10, the last of the chambers 124 discharges through a suitable conduit or opening 126 into a terminal compartment 127, which has the general form in section of an inclined shallow cylinder. At its outermost point heavy liquid is discharged through an opening 129 into the conduit 130, by which it is conveyed to the axial passageway leading from the rotor as hereinbefore described. Light liquid is introduced into the terminal compartment 127 at its innermost point through the conduit 130 and the opening 131.

The forms of compartments illustrated in Figs. 9 and 10 have the additional advantage that, when solid materials are present in the liquids being treated, their discharge is facilitated by the shape of the individual work compartments and terminal compartments formed in the rotor arm.

It will be noted in connection with the forms of construction shown in Figs. 9 and 10 that they are indicated as made in two parts, joined together as indicated at the partition lines 132, since the construction of these arms with compartments as indicated in these figures is fa cilitated by casting or otherwise shaping each half of the arm separately and subsequently welding or otherwise joining them.

Although the present invention has been described in connection with details of a specific embodiment thereof, it is not intended that these details shall be regarded as limitations upon the scope of the invention, except insofar as included in the accompanying claims.

I claim:

1. In apparatus for countercurrent exchange between liquids of different densities, a rotor having a radially extending arm with a cylindrical chamber formed therein extending outwardly from a point near the axis of rotation of the rotor to the outer extremity of said arm, radially spaced transverse perforated partitions and outwardly extending spacing members therebetween within said chamber to form a series of compartments therein extending from near its inner end to near its outer end, the perforations in said partitions being intermediate the sidewalls of said chamber, a removable plug for closing the outer end of said chamber, means for supplying heavier liquid to and withdrawing lighter liquid from said chamber at points near the axis of rotation, means for supplying lighter liquid to and withdrawing heavier liquid from said chamber at points more remote from the axis of rotation.

2. In apparatus for countercurrent exchange between liquids of different densities, a rotor provided with a chamber extending outwardly from the axis of rotation of the rotor and transversely of its path of rotation, said chamber being restricted laterally to extend through a minor proportion of the circular path of rotation of thc points near the axis of rotation of said rotor and means for supplying lighter liquid to and withdrawing heavier liquid from said chamber at points more remote from the axis of rotation of said rotor, and radially spaced. perforated partitions within said chamber extending transversely thereacross to form compartments therein, the perforations in said partitions having at le t one di sion in the range of 0.007 to 0.150 inch.

3. In apparatus for countercurrent exchange .between liquids of different densities, a rotor provided with a chamber extending outwardly from the axis of rotation of the rotor and transversely of its path of rotation, said chamber being restricted laterally to extend through a minor proportion of the circular path of rotation of .the rotor and the chamber, means for supplying heavier liquid to and withdrawing lighter liquid from said chamber at points near the axis of rotation of said rotor and means for supplying lighter liquid to and withdrawing heavier liquid from said chamber at points more remote from the axis of rotation of said rotor, and radially spaced perforated partitions within said chamber extending transversely thereacross to form compartments therein, the total area of the perforations in each of said partitions being not in excess of 5% of the clear area of the partitions.

4. In apparatus for countercurrent exchange between liquids of different densities, a rotor provided with a chamber extending outwardly from the axis of rotation of the rotor and transversely of its path of rotation, said chamber being restricted laterally to extend through a minor proportion of the circular path of rotation of the rotor and the chamber, means for supplying heavier liquid to and withdrawing lighter liquid from said chamber at points near the axis of rotation of said rotor and means for supplying lighter liquid to and withdrawing heavier liquid from said chamber at points more remote from the axis of rotation of said rotor, and radially spaced perforated partitions within said chamber extending transversely thereacross to form compartments therein, the distance between successive partitions being progressively reduced as an inverse function of their distance from the axis of the rotor.

S. In an apparatus for countercurrent exchange between liquids of different densities, a rotor having a radially extending arm provided with a restricted chamber extending through said arm from a point near the axis of rotation to a point more remote therefrom, means for supplying heavier liquid to and withdrawing lighter liquid from said chamber at points near the axis of rotation and means for supplying lighter liquid to and withdrawing heavier liquid from said chamber at points more remote from the axis of rotation, and radially spaced perforated partitions within said chamber and extending entirely thereacross to form compartments therein communicating only through the perforations in said partitions, said perforations being intermediate the side walls of said chamber and having at least one dimension in the range of from 0.007 to 0.150 inch.

6. In an apparatus for countercurrent exchange between liquids of different density, a rotor provided with a chamber extending outwardly from the axis of rotation of the rotor and transversely of its path of rotation, said chamber being restricted laterally to extend through a minor proportion of the circular path of rotation of the rotor and the chamber, means for supplying heavier liquid to and withdrawing lighter liquid from said chamber at points near the axis of rotation of said rotor and means for supplying lighter liquid to and withdrawing heavier liquid from said chamber at points more remote from the axis of rotation of said rotor, and radially spaced perforated partitions within said chamber extending transversely thereacross to form compartments therein, the

,percentoof the clear area of the partitions.

7. 1:11am apparatus for countercurrent exchange between liquids of different densities, a rotor provided with olnchamber extending outwardly from the axis of rotation -0f ,the rotor and transversely of its path of rotation, said chamber being restricted laterally to extend through a minor proportion of the circular path of rotation of the rotor and the chamber, means for supplying heavier liquid to and withdrawing lighter liquid from said chamber at .points near the axis of rotation of said rotor and means for supplying lighter liquid to and withdrawing heavier liquid from said chamber at points more remote from the axis of rotation of said rotor, and radially spaced perforated partitions within said chamber extending transversely thereacross to form compartments therein, the

12 distance betweensuccessive partitions being progressively reduced as an inverse function of their distance from the axis of the rotor, and the total area of the perforations in said partitions varying as an inverse function offla power of the radius from about 0.5 to 2.0.

References Cited in thefile of this patent UNITED STATES PATENTS 935,311 Laist Sept. 28, 1909 2,176,982 Thayer Oct. 24, 1939 2,234,921 Webb Mar. 11, 1941 2,266,553 Jones Dec. 16, 1941 2,281,796 Podbielniak May 5, 1942 2,286,157 Podbielniak June 9, 1942 2,619,280 Redlich Nov. 25, 1952 

